Railway braking apparatus



Dec. 24, 1929. J. P. COLEMAN RAILWAY BRAKING APPARATUS Filed Aug. 21. 1925 INVENTORZ y. f. MWM,

Mk ATTORNEY Patented Dec. 24, 1929 PATENT OFFICE JOHN P. COLEMAN, OF EDGENOGD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE,

RATION OF PENNSYLVANIA PENNSYLVANIA, A CORPO- RA ILWAY BRAKING APPARATUS Application filed August 21, 1925.

My invention relates to railway braking apparatus, and particularly to apparatus of the type comprising braking mechanism located in the t-raclrway and adapted to engage a part of a railway vehicle.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a view, partly diagrammatic, showing one form of railway braking apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a stretch of railway track. Associated with the rail 1 are two members 4 and 5 located on opposite sides of the rail and extending parallel therewith. A braking bar 2 extending parallel with the rail 1 is attached to member A bylsprings 6. A similar braking bar 3 is attached to member 5 by springs 6. In similar manner a member a carrying a braking bar 2 is located on one side of rail 1 and a member 5 carrying a braking bar 3 is located on the other side of rail 1.

The members 4, 5 and 4 5 are operated, through link work 7 by a lever 7 pivoted at point 27. As shown in the drawing, the braking mechanism is in its inefi'ective or non-braking position, that is, the braking bars are all retracted from the associated rails. When lever 7 is moved in a clockwise direction, bars 2 and 2 are moved to the right and bars 3 and 3 are moved to the left, so that these bars engage the wheels of a railway vehicle. The amount of the braking force exerted upon the railway vehicle depends upon the distance through which the members at, 5, 4F and 5 are moved, the difference in braking pressure being obtained by the difference in the compression of the springs 6. F

The braking mechanism which I have ust described and which is designated in general by the reference character K, is controlled by an electric motor A. This motor comprises the usual field structure A terminating in spaced pole pieces 9 and 9 and provided with a field winding 8. The motor also comprises an armature 10. Operatively connected with Serial No. 51,584.

armature 10 is a spindle 16 which is rigidly connected with a clutch member 17. The spindle 16 also carries a sleeve 17 which sleeve is loose on the spindle and is controlled by a lever 12 pivotally supported in a bracket 11 on the motor A. The lever 12 carries an armature 13 arranged to be attracted by flux traversing the air gap between pole pieces 9 and 9. A spring 53 biases the lever 12 to its upper position in which it is shown in the drawing. V] hen the field winding 8 is supplied with current, however, the left-hand end of lever 12 is moved downwardly, thereby moving the tip 19 of this lever to the right. The tip 19 engages a pin 18 in the sleeve 17 and moves the clutch member 17 into frictional engagement with the shoulder 21 on a worm 20. It follows that when the field winding 8 is energized, the worm 20 is operatively connected with armature 10 of motor A. hen field winding 8 is de-energized, lever 12 rises under the influence of spring 53, disconnecting the worm 20 from the armature 10.

The left-hand end of lever 12 carries an insulated contact member 14 arranged to ena contact finger 15 when the armature 13 is drawn downwardly. When lever 12 moves upwardly contact l4c15 is opened. The armature 10 is supplied with current from a suitable source of energy, such as a battery C, in series with contact 1415. It follows, therefore, that armature 10 is supplied with current only when the field winding 8 is energized.

The worm 20 meshes with the teeth of a gear 22 supported in journals not shown in the drawing. Rigidly connected with gear 22 is a pinion 23, which meshes with a segment gear 2 l supported on a shaft 25. This segment gear is provided with an arm 26, which is operatively connected with the lower end of the lever 7. With the apparatus in the condition illustrated in the drawing, the arm 26 of the segment gear 2% is swung to the right, and this position corresponds to the non-braking position of the braking mecha' nism K. lVhen motor A is operated to rotate the segment gear 24 in clockwise direction, as shown in the drawing, arm 26 is moved contacts 33-37 and 34-41 are closed.

rent then flows from the battery C, through to the left, thereby swinging lever 7 in clockwise direction and moving the braking mechanism to its efiective or braking position.

The reference character D designates an automatic circuit controller comprising a lever 28 pivoted at point 28 and arranged to engage with a plurality of contact segments 29, 30, 31 and 32. The lever 28 is operatively connected with the arm 26 of segment gear 24. When the segment gear is in such position that the braking mechanism K is in its non-braking position, contacts 28-29, 28-30, and 28-31 are all closed. As the arm 26 moves to the left to operate the braking mechanism towards its position of maximum braking effort, these three contacts are successively opened in the order named. Contact 28-32 is open only when the mechanism K is in its non-braking position.

The reference character B designates a manually operable circuit controller comprising two movable levers 33 and 34 connected by an insulated handle 35. The lever 33 is arranged to engage any selected one of a plurality of contacts 36, 37, 38 and 39. When lever 33 engages with contact 36 lever 34 engages afixed contact 40. For all other positions of the lever 33 the lever 34 engages a contact segment 41.

As shown in the drawing, contacts 33-36 and 34-40 of circuit controller B are closed,

I and the braking mechanism K is in its ineffective position.

Contacts 28-29, 28-30 and 28-31 are therefore closed and contact 28-32 is open. The field winding of motor A is de-energized so that the left-hand end of lever 12 is in its upper position. In explaining the operation of the apparatus I will first assume that the operator wishes to make a light brake application. To do so he moves the circuit controller B to such position that Curwire 42, contact 33-37 of circuit controller B, wire 43, contact 29-28 of circuit controller D, wire 44, field winding 8 of motor A,

'wires 45 and 45, contact 41-34 of circuit controller B, and wire 46 back to battery C. The flux created in the field structure A by the current thus supplied to field winding 8 attracts armature 13 and draws the left-hand end of lever 12 downwardly. The worm is therefore operatively connected with the armature 10, and the closing of contact 14-15 the worm 20 therefrom. If the braking mechanism is moved toward its non-braking position as by the efiect of the railway vehicle passing over the rails 1 and 1 the consequent closing of contact 29-28 immediately re-establishes the circuits just traced for the motor A and the braking mechanism is restored to braking position. It will be plain that when the contact 33-37 of circuit controll'er B is closed, the motor A moves the braking mechanism only acomparatively short distance toward its maximum braking position. If the operator wishes to exert a more powerful braking force, he closes contact 33-38 of circuit controller B. Contact 34-41 is still closed, and current therefore flows from battery C through wire 42, contact 33-38 of circuit controller B, wire 47, contact -28 of circuit controller D, wire 44, field winding 8 of motor A, wires and 45, contact 41-34 of circuit controller B and wire 46 back to battery C. With the field winding of the motor energized over this circuit, the operation of the apparatus is similar'to that described in connection with contact 33-37 of circuit controller B with the single exception that the contact 30-28 of circuit controller D allows the braking mechanism to be moved a greater distance towards its braking position before the motor circuit is interrupted. Similarly, if contact 33-39 of circuit controller B is closed, current fiows from battery C, through wire 42, contact 33-39 of circuit controller B, wire 48, contact 31-28 of circuit controller D, wire 44, field winding 8 of motor A, wires 45 and 45, contact 41-34 of circuit controller B, and wire 46 back to battery C. When the motor A is energized over this circuit, the contact 31-28 controls the field circuit for the motor A and permits the braking mechanism to be moved to its maximum braking position before the motor circuit is opened. It will be plain from the foregoing that the operator can obtain a plurality of braking pressures corresponding to the plurality of contacts in circuit controllers Band D. Since each of the contacts in the circuit controller D opens the'motor circuit after the braking mechanism has been moved a diiferent amount toward the braking position, it follows that each of these contacts corresponds to a different magnitude of braking effort.

In order to restore the braking mechanism to its non-braking position, the operator closes contacts 33-36 and 34-40 of circuit controller B. Current then flows from battery C, through wire 42, contact 33-36 of circuit controller B, wires 52 and 45, field wind ing 8 of mo-tor A, wire 44, contact 28-32 of circuit controller D, wire 53, contact 40-34 of circuit controller B, and wire 46 back to battery C. It will be observed that the relative polarity of the current supplied to the field winding 8 over this circuit is opposite to the polarity of the current supplied to that winding over the circuits already traced for moving the braking mechanism to its braking position. The motor A is therefore operated in such direction that the braking mechanism is moved toward its non-braking position. hen the braking mechanism has reached its full non-braking position, contact 3228 of circuit controller D opens, interrupting the motor circuit and allowing lever 12 to move upwardly, thus restoring the apparatus to its original condition.

Although I have herein shown and described only one form of railway braking apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A car retarder comprising, braking mechanism, an electric motor for operating said mechanism and having a field winding and an armature, manually operable means for at times supplying current to said field winding, and means responsive to current in said field winding for automatically supplying current to said armature.

2. A car retarder comprising, an electric motor having a field winding and an armature, braking mechanism, means for at times supplying current to said field winding, and means responsive to current in said field winding for automatically supplying current to said armature and for operatively connecting said armature with said mechanism.

3. A car retarder comprising braking mechanism, an electric motor, irreversible gearing interposed between said motor and said mechanism whereby the motor can move the mechanism to and from its maximum braking position but the mechanism cannot rotate the motor, a circuit controller comprising a plurality of contacts closed when sait mechanism is in its fully retracted position and successively opened as the mechanism moves towards its full braking position, a source of current, manually operable means for connecting said source with the field winding of said motor through any selected one of said contacts, and means responsive to current in said field winding for automatically supplying current to the armature of said motor.

4. A car retarder comprising braking mechanism, an electric motor, irreversible gearing interposed between said motor and said mechanism whereby the motor can move the mechanism to and from its maximum braking position but the mechanism cannot rotate the motor, a circuit controller comprising a plurality of contacts closed when said mechanism is in its fully retracted position and successively opened as the mechanism moves towards its full braking position, a source of current, manually operable means for connecting said source with the field winding of said motor through any selected one of said contacts, and means responsive to current in said field winding for automatically supplying current to the armature of said motor and for operatively connecting said armature with said braking mechanism.

5. A car retarder comprising braking mechanism, an electric motor, irreversible gearing interposed between said motor and said mechanism whereby the motor can move the mechanism toward and away from its full braking position but the mechanism cannot rotate the motor, a plurality of contacts closed when said mechanism is in its fully retracted position and successively opened as the mechanism moves toward its full braking position, a source of current, manually operable means for connecting said source with the field winding of said motor in one direction through any selected one of said contacts and for at other times connecting said source with the field winding of said motor in the other direction, and means responsive to current in said field winding for automatically supplying current of constant relative polarity to the armature of said motor.

6. A car retarder comprising braln'ng mechanism, an electric motor having the usual field winding and rotatable armature as well as an auxiliary tractive armature responsive to current in the field winding, and means controlled by said auxiliary armature for operatively connecting said rotatable armature with said braking mechanism.

7. A car retarder comprising braking mechanism, an electric motor having the usual field winding and rotatable armature as well as an auxiliary tractive armature responsive to current in the field winding, a clutch interposed between said rotatable armature and said braking mechanism, and means for engaging said clutch when and only when said auxiliary armature is attracted in response to current in the motor field winding.

In testimony whereof I afiix my signature.

JOHN P. COLEMAN. 

